Device for automatic re-setting of telewriter to letter-printing position



29, 1961 K. WEBER ET AL 2,998,484

DEVICE FOR AUTOMATIC RE-SETTING OF TELE-WRITER TO LETTER-PRINTING POSITION Filed 001.. 13, 1958 FIG. 2

' IN V EN TQR Kare/U060; farax/ar awa BY MM m y United stat men 2,998,484 DEVICE FOR AUTOMATIC RE-SETTING F TELE- WRITER T0 LETTER-PRINTING POSITION Karel Weber and Jaroslav vafia, Hradec Kralove, Czechoslovakia, assignors to Tesla, narodni podnik, Prague,

Czechoslovakia Filed Oct. 13, 1958, Ser. No. 766,757 1 'Claim. (Cl. 178-23) This invention relates to a device for the automatic re-setting of a tele-writer to its letterrintin osition the p g p sideration of the detailed description of a specific illustrative embodiment thereof presented hereinbelow in condevice comprising two control contacts which are mechanically operated by the tele-Writer type wheel and which are connected in the control circuit of an'electromagnet which is arranged to switch the type wheel from i open, the electromagnet cannotbeenergized and the type the position in which letters are printed to the position corresponding to the printing of numbers and marks.

The outstanding feature of a device illustratively embodying the principles of this invention resides in thefact that a tele-writer with which such a device is combined oper-j ates smoothly and without undue troubles and errors;

which in present tele-writer systems in which theinitial position of the type wheel is not exactly defined.

When a tele-Writer is started by manual or automatic means or when communication is initiated by direct interconnection of two te-le-writers, either a letter or a number or a mark is printed as soon as the driving motor and the mechanical controlling members start to move. Additionally, there is another drawback inherent in preserit tele-writers, namely, that due to the difierent operating positions of two machines at the instant when communication therebetween is initiated. For instance, the local machine may be set to print letters, whereas the distant one is set to print numbers and marks.

The above-specified drawbacks of 'known tale-writers may lead to errors therein and, as a result, cause the lowering of the speed of communication due to the necessity of repeating the transmission of information.

The basis of the shortcomings mentioned above lies in the fact that line-current for the tele-writer receiving magnet as well as source voltage for the tele-writer motor is cut off as soon as actual communication of the tele- Writer is stopped. The dropping electromagnet and the decelerating motor, however, still actuate some members of the tele-writer control system. :When the tele-writer is again started, the source voltage is applied to the driving motor and the receiving electromagnet is energized by the line-current. Therefore, some control members are again actuated until the Stop position of all elements is reached. This intermediate state of operation causes erroneous prints.

The device to which the present invention relates gets rid of the above mentioned shortcomings, whereby, when starting a tale-writer by manual or automatic means or by means of a direct interconnection between two tele- Writers, the machines are automatically reset to their letter-printing positions.

In both terminal positions of the type wheel of an illustrative embodiment of the principles of the present invention, i.e., in the position corresponding to the printing of letters and in that corresponding to the printing of numbers and marks, one of two controlling contacts is active, each of these two contacts being used for switching over the type wheel from one position to the other. The embodiment also includes an electromagnet and a control circuit therefor including two branches. In both branches of the electromagnet control circuit contacts of storage relays are connected. When the tele-writer is started, relays for the reception of pulse combinations send equal current pulses to all storage relays (this being equivalent to the letter symbol). If the type wheel finds marks, and vice versa.

wheel remains in the letter-printing position. On the contrary, if the initial position of the type wheel corresponds to the number printing position, the respective control contact is closed, the electromagnet is energized and switches the type wheel over into the position for letterprinting.

The above and other advantages and features of the present invention will be better understood from a conjunction with the accompanying drawing, in which:

FIG. 1 is a diagrammatic showing of the reception con ples of the present invention.

The showing of FlG.- -3 of the drawing comprises an electromagnet M and a control circuit therefor, which electromagnetactuates a mechanism in a tele-writer for switching over the type wheel thereof from the'letter printing position to the position for printing numbers and The control circuit comprisestwo branches which respectively include contacts I and H. In FIG. 3, both these contacts are shown enclosed withina dashed-line box. The control circuit also includes contacts a d 0 and 12 while in the first branch the con-- tact 2 (and I) .and in the second one the contact e (and II)- are connected. All of the contacts a b c d and e: and e belong to the storage relays (FIG. 2) which receive pulses from relays H I J K L In the OE position of the tele-writer the reception relay is de-energized and its armature assumes the position AT. The relays and are de-energized as well, since in that condition of the tele-writer no voltage is applied to the windings of these relays.

Now, when the tele-writer is switched on, the reception relay may be actuated, but they get immediately de-energized, since the positive pole from the relay and the contact OK of the mechanism RIPK are disconnected. Thereby, the releasing reception relays transmit the letter symbol (all five current pulses) over the contacts the storage relays The storage relays are, therefore, actuated, their associated contacts are closed and, as seen in FIG. 3, according to the position of the contacts I and II, the electromagnet M either is energized or remains de-energized.

As stated above, the electromagnet M serves to mechanically switch the type wheel of the tele-Writer from its letter-printing position to its numbers and marks position, or vice versa.

The device according to the present invention causes, therefore, the type wheel to remain in the letter position after the tele-writer has been started in case the initial position of the type wheel was the letter-printing position.

This is because the contact I remains, in that position of the type wheel, open, so that even when all of the relays A B C D E are energized, the electromagnet M receives no current. If, on the other hand the initial position of the type-wheel was that corresponding to number and mark printing, the contact I is closed and as soon as the tele-writer has been started, the type wheel is automatically switched over by the electromagnet M into the position for letter printing.

What We claim is:

In combination in a tele-writer of the type which may be either in a letter-printing or a numberand markprinting condition, electromagnet means for switching the tele-Writer between the two conditions, relay means, circuit means for energizing said electromagnet means, said circuit means including switching means and contact members, said contact members being controlled by said relay means, said switching means being in an open-circuit position when the tele-writer is in its letter-printing condition and being in a closed-circuit position when the tele-writer is in its numberand mark-printing condition, and means responsive to the turning on of the tele-writer 25 for energizing said relay means, thereby causing said contact members to be actuated and, if said switching means is initially in a closed-circuit position, causing said electromagnet means to be energized to switch the telewriter to its letter-printing condition and, if said switch- 30 ing means is initially in an open-circuit position, not

causing said electromagnet means to be energized thereby leaving the tele-writer in its letter-printing condition.

References Cited in the file of this patent UNITED STATES PATENTS 2,326,298 Hewitt Aug. 10, 1943 2,333,318 Krum Nov. 2, 1943 2,720,832 Luning Oct. 18, 1955 

